The present invention is directed to sensing devices and their processing. More particularly, the invention provides a method and apparatus for sensing electromagnetic radiation in the infrared spectrum using a tunable bolometer device. But it would be recognized that the invention has a much broader range of applicability. For example, the invention can be applied to other wavelengths such as millimeter waves or visible light and others.
As technology progresses, detection devices have become important. Detection devices range from motion sensors to those that detect certain frequencies of electromagnetic radiation. Such detection devices include, among others, infrared detectors and imagers. As merely an example, conventional infrared detectors, commonly known as bolometers, received interest from their ability to detect infrared radiation through changes in temperature. Preferably, such bolometers work at room temperature, but can also work at other temperatures.
Many applications emerged using these conventional bolometer devices. Night vision techniques evolved with such infrared radiation detectors. That is, infrared radiation emitted from warm bodies are detected using an array of sensing devices on infrared detectors. Other types of applications include chemical detection and the like. For these applications, other types of conventional bolometer devices have been used.
Conventional bolometers often include passive absorbent layers that detect infrared radiation. These passive layers include metals that absorb infrared radiation and convert such radiation into an increase in temperature. The passive absorbent layers operate within a range of large spectral sensitivity. Accordingly, limitations exist with such conventional bolometer devices. Large spectral sensitivity allows for detection of more than one frequency of incoming infrared radiation. That is, these devices cannot often detect a spectral composition or specific frequencies of the incoming infrared radiation. These and other limitations may be discussed throughout the present specification and more particularly below.
From the above, it is seen that an improved technique for processing devices is desired.